Dubious decision evidence and criterion flexibility in recognition memory.

When old-new recognition judgments must be based on ambiguous memory evidence, a proper criterion for responding "old" can substantially improve accuracy, but participants are typically suboptimal in their placement of decision criteria. Various accounts of suboptimal criterion placement have been proposed. The most parsimonious, however, is that subjects simply over-rely on memory evidence - however faulty - as a basis for decisions. We tested this account with a novel recognition paradigm in which old-new discrimination was minimal and critical errors were avoided by adopting highly liberal or conservative biases. In Experiment 1, criterion shifts were necessary to adapt to changing target probabilities or, in a "security patrol" scenario, to avoid either letting dangerous people go free (misses) or harming innocent people (false alarms). Experiment 2 added a condition in which financial incentives drove criterion shifts. Critical errors were frequent, similar across sources of motivation, and only moderately reduced by feedback. In Experiment 3, critical errors were only modestly reduced in a version of the security patrol with no study phase. These findings indicate that participants use even transparently non-probative information as an alternative to heavy reliance on a decision rule, a strategy that precludes optimal criterion placement

Modeling the Behavior of the Surface to Liquid Interfaces in an Electrolytic Liquid

Understanding the mechanism for charge transfer between electrodes within an electrolyte dissolved in water is vital to better understanding the sources of electrical noise in the system. This research compares the electrical properties of liquid top gated graphene devices with the properties of two metal probes to model the system. By measuring the impedance of these systems at different frequencies, it is possible to develop a model of their electrical properties and to consider techniques to improve signal to noise at graphene interfaces

Simulated effects of management and mating systems upon life-cycle production efficiency in swine

The systems concept of swine production research incorporates an awareness that there is more to consider than merely the level of production and implies that an enterprise is a system of many components which all play a part in determining net return. While level of production is an important factor affecting profitability, production costs are equally important. Numerous factors influence swine production and this information must be integrated to determine how enterprise profitability is affected. Five pork production systems were simulated using a deterministic computer model to analyze the effect that lactation length, estrus at initial mating, estrus at post-weaning mating and maximum parity have on the efficiency of producing 200 litters per year. Under this approach, production inputs were treated as dependent variables determined by animal performance. Mating gilts at first estrus does not appear to provide a means to improved efficiency, but this system does reduce overall facility requirements, which in turn reduce capital outlay and risk. Mating sows at first versus second estrus following weaning after a 35-day lactation improved feed efficiency and facility utilization. Production costs declined from 98.11 to 94.73 per 100 kg of pork marketed, increasing net profit by 5086. Decreasing maximum parity from five down to one increased the number of replacement gilts entering the breeding herd annually which resulted in poorer reproductive performance, fewer market hogs, and a larger percentage of pork marketed as culled breeding stock. Reducing maximum parity from five to one decreased income as well as increased production costs. Production efficiency improved when lactation length declined from 35 to 18 days as a result of decreased feed, depreciation and capital charges. This result occurred in spite of a decline in litter size due to early weaning. The simulated results conclude that increasing reproductive rhythm, tightening farrowing schedules and farrowing continuously offer producers opportunities to boost sow productivity, make more efficient use of facilities and improve herd efficiency

Dynamics of Co-translational Membrane Protein Integration and Translocation via the Sec Translocon

An important aspect of cellular function is the correct targeting and delivery of newly synthesized proteins. Central to this task is the machinery of the Sec translocon, a transmembrane channel that is involved in both the translocation of nascent proteins across cell membranes and the integration of proteins into the membrane. Considerable experimental and computational effort has focused on the Sec translocon and its role in nascent protein biosynthesis, including the correct folding and expression of integral membrane proteins. However, the use of molecular simulation methods to explore Sec-facilitated protein biosynthesis is hindered by the large system sizes and long (i.e., minute) timescales involved. In this work, we describe the development and application of a coarse-grained simulation approach that addresses these challenges and allows for direct comparison with both in vivo and in vitro experiments. The method reproduces a wide range of experimental observations, providing new insights into the underlying molecular mechanisms, predictions for new experiments, and a strategy for the rational enhancement of membrane protein expression levels

FARM-LEVEL RESPONSE TO AGRICULTURAL EFFLUENT CONTROL STRATEGIES: THE CASE OF THE WILLAMETTE VALLEY

This article examines economic incentives and other mechanisms to offset non-point source pollution from agriculture. A biophysical simulator to estimate technical relationships is linked to linear programming models for representative farms in the Willamette Valley of Oregon. The models are then optimized for profit maximization under alternative non-point pollution control policies. The results indicate that site-specific resource conditions and production possibilities greatly influence policy effectiveness and the cost of achieving pollution abatement. Nevertheless, some abatement is possible on all farms for relatively little cost.Environmental Economics and Policy,

In Touch with Prairie Living, March 2017

March 2017 column for North Dakota and South Dakota newspapers

In Touch with Prairie Living, January 2008

January 2008 column for North Dakota and South Dakota newspapers